Suchergebnisse

The most severe biotic crisis on Earth history occurred during the Permian–Triassic (PT) transition around 252 Ma. Whereas in the marine realm such extinction event is well-constrained, in terrestrial settings it is still poorly known, mainly due to the lack of suitable complete sections. This is utterly the case along the Western Tethys region, located at Pangaea's equator, where terrestrial successions are typically build-up of red beds often characterised by a significant erosive gap at the base of the Triassic strata. Henceforth, documenting potentially complete terrestrial successions along the PT transition becomes fundamental. Here, we document the exceptional Coll de Terrers area from the Catalan Pyrenees (NE Iberian Peninsula), for which a multidisciplinary research is conducted along the PT transition. The red-bed succession, located in a long E-W extended narrow rift system known as Pyrenean Basin, resulted from a continuous sedimentary deposition evolving from meandering (lower Upper Red Unit) to playa-lake/ephemeral lacustrine (upper Upper Red Unit) and again to meandering settings (Buntsandstein facies). Sedimentary continuity is suggested by preliminary cyclostratigraphic analysis that warrants further analysis. Our combined sedimentological, mineralogical and geochemical data infer a humid-semiarid-humid climatic trend across the studied succession. The uppermost Permian strata, deposited under an orbitally controlled monsoonal regime, yields a relatively diverse ichnoassemblage mainly composed of tetrapod footprints and arthropod trace fossils. Such fossils indicate appropriate life conditions and water presence in levels that also display desiccation structures. These levels alternate with barren intervals formed under dry conditions, being thus indicative of strong seasonality. All these features are correlated with those reported elsewhere in Gondwana and Laurasia, and suggest that the Permian–Triassic boundary might be recorded somewhere around the Buntsandstein base. Consequently, Coll de Terrers and the whole Catalan Pyrenees become key regions to investigate in detail the Permian extinction event and the Triassic ecosystems recovery. © 2017 Elsevier B.V. ; E. Mujal obtained financial support from the PIF grant of the Geology Department at UAB, and from the Erasmus + program of the UAB performed at the Palaeontology Department from the Institut des Sciencies de l'Evolution (Université de Montpellier, France). E. Mujal received funding from the SYNTHESYS Project http://www.synthesys.info/ (FR-TAF-3621, FR-TAF-4808) which is financed by European Community Research Infrastructure Action under the FP7 "Capacities" Program. J. Fortuny acknowledges the support of the postdoc grant "Beatriu de Pinós" 2014 – BP-A 00048 from the Generalitat de Catalunya as well as from the Spanish Ministerio de Economía, Industria y Competitividad and the European Regional Development Fund of the European Union (MINECO/FEDER EU, project CGL2014-54373-P). J. Pérez-Cano acknowledges the support from the Spanish Ministerio de Economía, Industria y Competitividad (FPI grants BES-2016-076469). This work received support from CERCA programme at Institut Català de Paleontologia (ICP) and from the projects "Vertebrats del Permià i el Triàsic de Catalunya i el seu context geològic" and "Evolució dels ecosistemes amb faunes de vertebrats del Permià i el Triàsic de Catalunya" (ref. 2014/100606), based at ICP and financially supported by the Departament de Cultura (Generalitat de Catalunya). ; Peer reviewed